095
FXUS63 KIWX 131827
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
227 PM EDT Sun Jul 13 2025

.KEY MESSAGES...

- Some smoke aloft from Canadian wildfires is expected to spread across
  the region today and into Monday, particularly across the
  upper Great Lakes.

 - Scattered showers and storms this afternoon and evening,
   especially south of US 24.

- A brief reprieve from higher humidity today into Monday but
  peak afternoon heat indices return into the 90s for Tuesday
  and Wednesday.

- Next chances for rain/storms arrive midweek, especially Wednesday
  and Thursday in the afternoon and evening.


&&

.DISCUSSION...
Issued at 224 PM EDT Sun Jul 13 2025

The cold front that moved through yesterday has slowed and is
currently draped from Toledo, OH southeast to just north of the
St Louis metro. There is a low level theta-e gradient across
the area today, with the best temperature and moisture found
along and south of the US 24 corridor. This area is also where
dewpoints are in the upper 60s to low 70s. As the front moves
through the rest of our forecast area this afternoon/evening,
scattered showers and a few isolated storms should develop
across north central Indiana. Much like the set up yesterday,
there is some instability for storms to tap into but shear is
very low so storms will remain sub-severe. Lightning, briefly
heavy rain, and gusty winds to 30-40 mph will all be potential
hazards along and south of US 24. Showers will gradually taper
off into the overnight hours.

Tonight, skies will clear out behind the front and winds will be
light and variable. Patchy fog will be possible, especially in areas
where showers and storms have moved through over the past 24 hours.
Leftover moisture near the surface should help allow for radiation
fog to form along and south of US 24 by early Monday morning.

In addition, wildfire smoke from Canada continues to drift into
across the Upper Great Lakes region. The greatest impacts to
air quality are expected across the UP and Northern Lower
Michigan, however, the statewide Michigan Air Quality Alert has
been expanded through the day Monday. It is possible that smoke
aloft gets as far as northern Indiana and far northwest Ohio,
making for hazy skies. Surface air quality should not be
impacted.

Heat and humidity will increase over the next few days,
especially on Tuesday. Southerly low level flow and WAA will
usher in low to mid 70s dewpoints on Tuesday and Wednesday, with
a notable increase in humidity. Highs will be in the upper 80s
to low 90s, with peak heat indices in the 90s. Mid range model
guidance has been persistent with an active pattern reemerging
by midweek. A 500mb shortwave will aid in thunderstorm
development as it pivots through the area Wednesday
afternoon/evening. Additional shortwaves pivot through Thursday
and a cold front sweeps through, with additional showers and
storms possible. Our typical summertime pattern of high
instability and minimal shear looks to set up once again, so it
is too far out to determine whether there will be any severe
potential with these storms. By the weekend, dry conditions
return with zonal flow over the Upper Great Lakes.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 133 PM EDT Sun Jul 13 2025

A shortwave approaches from the southwest and provides an area of
showers and perhaps a few thunderstorms to areas south of US-24,
however, models do appear to keep the storms south of FWA so will
keep the threat out of both TAFs this time. As a result, VFR
conditions will prevail as mid level cloud decks move in for the
afternoon with the arrival of the shortwave. CIGs drop as we head
into the overnight and winds relax. A few short range models are
creating fog once again this evening, but a theta-e boundary bisects
the area into north and south regions tonight right overhead of FWA.
This environment should keep even FWA out of fog chances as well so
will continue with the prevailing VFR conditions. Winds stay under
10 kts for the period.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...None.
OH...None.
MI...Air Quality Alert until midnight EDT Monday night for
     MIZ078>081-177-277.
MARINE...None.

&&

$$

DISCUSSION...Johnson
AVIATION...Roller